The spectre of death continues to haunt Tihar jail in Delhi, with a warden succumbing to tuberculosis, taking the number of deaths in Asia's largest prison to seven in as many days, prompting the Delhi government and the National Human Rights Commission to launch a probe.

Man Singh (58), a head warden, died on Tuesday night at his quarters inside the jail. He had been under treatment for tuberculosis for the last several years, prison officials said.

Singh, who was to retire from service in 2009, had been undergoing treatment for TB at the army hospital in Delhi.

The jail hit the headlines after six inmates died in as many days, prompting the administration to carry out daily medical check-ups of the prisoners and install coolers and exhaust fans to beat the scorching summer.

Two deaths were reported on Tuesday. While Vinod Kumar, an alcoholic, died in the jail hospital in the morning, a convict identified as Santosh died later in the day at the DDU hospital where he was admitted on June 4.

The unusual series of deaths also prompted the Delhi government to order a magisterial inquiry and the NHRC to launch a probe.

The high court has also sought explanation from the city administration and the jail authorities about the deaths.

According to government figures, Tihar is bursting at its seams with a population of nearly 12,500 inmates far exceeding the sanctioned capacity of 5,000.

It is also grappling with a daunting health hazard -- drug abuse -- as around 10 per cent of inmates are drug addicts.